Conventionally, a system for observing or predicting meteorological weather based on signals from a radar.
With a method of predicting thunder disclosed in Patent Document 1 (JP1997-329672A), a type of a precipitation particle is identified and a possibility of thunder occurrence is predicted, based on a radar reflectivity factor with respect to a horizontally polarized wave of a dual-polarization radar and a radar reflectivity factor difference between horizontally and vertically polarized waves.
Further, with a system disclosed in Patent Document 2 (JP1999-281740A), an approximate location of a meteorological phenomenon, such as a rain cloud, is detected by a search radar with a low resolution using a fan beam, and an accurate location of the meteorological phenomenon, such as the rain cloud, is detected by an observation radar with a high resolution using a pencil beam.
A meteorological radar apparatus in Patent Document 3 (JP2010-256333A) includes an active phased array antenna unit in which a plurality of antenna elements which transmit a radar pulse and receive a refection pulse are vertically arrayed, so as to obtain a rainfall intensity and a Doppler velocity in short time.